Alliance Pipeline tested hydrophobic (High-Efficiency Particulate Air) HEPA filters on two of its pipeline compressors. In a year of field testing, Alliance found that these filters had the same pressure drop as existing, lower efficiency filters, and that they eliminated the need to shut down compressors for off-line water washing (OLWW).

Compressor fouling and blade corrosion due to ingress of contaminants in the incoming air (dust, soot, salt, etc) has been an all too common problem for gas turbine operators, requiring frequent compressor washing.